Fuel Pump issues

02 MC 209-X9-LTR 330HP

I had a fuel pump go on my boat @ about 160hrs...the rear shower was left on and it may have gotten soaked...so I was okay with that...It went again last year @ 420hrs i had it replaced...the mechanic said it looked like the wiring was not a great connection...he replaced it...with out fixing the wiring ...I ran ithte restof last year and I had about 4 hrs on my boat this year so about 460hrs and she died again..took it in..fuel pump...perhaps stemming from the bad connection last year...brand new fuel pump...less than an hour..boat stalls out again...fuel pump is shot...
Bad wiring? bad ground..to burn up the pump..
I have heard that if i moore the boat in a marina...like I do..I could actually get my wiring "attacked" though the water by other boats near it with bad grounds...has ANYONE EVER HEARD OF THAT?
regardless..i have another fuel pump on it's way and am having the wiring traced back and re wired from the source...any comments or suggestions...similar experiences?